JP4646643B2 - Recording device - Google Patents

Description

  The present invention relates to a large-format recording system using a plurality of recording modules each having a recording head.

In an inkjet printer equipped with a line head, in order to prevent a reduction in the life of the recording head, conventionally, an ink discharge is dispersed by shifting an image for each predetermined page so that a load is not concentrated on a specific nozzle. There is something.
(For example, Patent Document 1)
There has also been proposed a method in which a plurality of heads of the same color are mounted to perform higher-speed recording and ink ejection is dispersed by a method called raster division.
(For example, Patent Document 2)

JP 07-047714 A Japanese Patent Application No. 2004-049447

However, since the image position on the recording medium is shifted in the horizontal direction in the method of Patent Document 1, even a slight shift may be a problem depending on the image contents. A slight shift amount may have a low effect on the durability (life) improvement of the recording head.
On the other hand, according to the method of Patent Document 2, since a plurality of line heads of the same color are mounted and divided and recorded for each raster (row perpendicular to the conveyance direction of the recording medium), durability can be considerably improved. However, the assigned raster for each recording head is uniquely fixed.
This type of recording apparatus is required to have very high productivity, and the recording speed is almost proportional to the number of recording heads mounted. Therefore, since the replacement frequency of the recording head due to the lifetime is high, means for improving the lifetime is important. In the first place, the life of the recording head is a measure of how many times the ink is ejected cumulatively from one ink ejection nozzle, and there is an example where the nominal value is, for example, around 5 × 10 ⁸ [times / Nozzle].
Considering a line head having 2560 [Nozzle], 5 × 10 ⁸ [times / Nozzle] × 2560 [Nozzle]
Therefore, it is important to bring the cumulative total number of recording pixels close to the ideal value as the life of the recording head.
In addition, in the thermal ink jet system in which the nozzle is heated by a heater, the maximum temperature reached near the heater itself or in the vicinity of the heater is also a major factor that determines the durability, so bursts to a specific nozzle can also be used to average the heat storage near the nozzle. Needless to say, it is preferable to avoid the recording signal and distribute it.

  In order to solve the above problems, the present invention has been devised and the following means have been realized.

That is, the present invention includes a medium transport unit that transports a long recording medium in a predetermined transport direction and four recording heads that eject ink of the same color, each of which is responsible for the four recording heads. , By recording on a raster in a direction intersecting the transport direction, the four continuous rasters are shared to complete an image on a recording medium, and the recording is divided for each raster in the direction intersecting the transport direction. generating data, the recording data to which the four recording heads each have divided corresponding to the raster in charge has control means for transferring to a corresponding respective said four recording heads, wherein the control means , for each page, when changing the raster said four recording heads is responsible, change the records for each of the raster to charge according to the order in which each is predetermined for the four recording heads And wherein the Rukoto.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the relative arrangement, numerical formulas, numerical values, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified.

  FIG. 1 is a perspective view schematically illustrating a recording unit of a recording apparatus embodying the present invention.

The recording unit 100 of the recording apparatus includes four recording heads 101 to 104 that eject ink of the same color (for example, black), and these images are recorded at a position shown in FIG.
A plurality of labels 106 temporarily attached onto a mount of roll paper 105 wound in a roll shape are fed out in the direction of the recording head, and then conveyed at a constant speed by conveying motors 108 to feed rollers 109, and the recording heads 101 to 104. After passing through the lower part of the label, the recorded label 107 is continuously discharged. When the front end of the label 106 is detected by a paper front end detection sensor 111, each recording head 101 to 104 records each assigned raster in synchronization with the output of the rotary encoder 110 coupled to the motor shaft of the transport motor 108.
Reference numeral 112 is also a paper leading edge detection sensor used for detecting a paper jam.

FIG. 2 is an electrical block diagram of a recording apparatus embodying the present invention. The recording data on the paper is created by the host PC 200 and transferred to the interface controller 201 of the recording apparatus.
The recording data received by the interface controller 201 is not different from conventional recording data. The memory controller 206 temporarily writes the received data in the image buffer 207 at a high speed according to an instruction from the CPU 202.
After receiving a predetermined amount of recording data, the CPU 202 enters preparation for recording operation of the recording unit 100.

First, the head U / D motor 211 and the cap motor 212 are operated with each other via the drive unit 210, and the recording heads 101 to 104 that have been capped in a standby state by a cap mechanism (not shown) are moved to the recording position. To do. At this time, the recording heads 101 to 104 move up and down, and a cap mechanism (not shown) moves forward and backward in a direction parallel to the paper transport direction.
Subsequently, the roll paper 105 is fed out by a roll paper supply motor (not shown),
Further, the transport motor 108 is also activated via the drive unit 217. The start of the transport motor 108 is triggered by the speed instruction value of the transport motor 108 serving as a servo motor being written from the CPU 202 to the servo logic circuit 216.

  Thereafter, the output of the rotary encoder 110 is fed back to the servo logic circuit 216, and constant speed control is performed in the feedback loop of the drive unit 217, the transport motor 108, the rotary encoder 110, and the servo logic circuit 216.

  The servo logic circuit 216 converts the output from the rotary encoder 110 into a conveyance position pulse and outputs it as a cutout signal for each recording head 101 to 104 to perform raster recording.

Then, when the leading end of the label 106 is detected by the leading end detection sensor 111 on the upstream side in the transport direction, when the transport position pulse corresponding to the distance of each of the recording heads 101 to 104 is received from the leading end detection sensor 111, the memory controller 206 receives it. Then, reading of the image buffer 207 is started and transferred to the recording head control circuit 208. In the recording head control circuit 208, the recording heads 101 to 104 try to generate recording data for all rasters with different cut-out timings, but each recording head is not responsible for the transfer output unit to the recording heads 101 to 104. The recording data for raster (3 rasters out of 4 rasters) is masked. The mask method is a characteristic part of the present invention and will be described later with reference to FIGS.

  A mounting space for the recording heads 101 to 104 may be provided with a spare mounting space. Reference is made to the recording heads shown in FIG.

  The processing of the CPU 202 depends on the control program written in the ROM 203, but the RAM 204 is also used for work. The EEPROM 205 is a non-volatile memory that stores numerical values unique to the apparatus such as an adjustment value for electrically adjusting a minute recording position (registration) between the recording heads. The recording device is equipped with an operation panel 219 including a display device such as an LCD and a pause / resume / emergency stop key for the recording operation. Display data can be written and the ON / OFF state of the key can be read via the input / output port 209. It is.

  Output analog values of the leading edge detection sensors 111 and 112 of the paper and the internal temperature sensor (220) of the recording apparatus can be read out almost in real time via the AD converter 218.

  The pump motor 213 is used when ink is supplied from an ink tank (not shown) to the recording heads 101 to 104 or when the inside of the recording head is pressurized to restore sound recording performance by forcibly discharging ink from the ejection nozzle. The illustrated pump is driven.

  Next, a method of changing the raster assigned to each of the recording heads 101 to 104 according to the present invention at predetermined intervals will be described with reference to FIGS.

  FIG. 3 shows a state in which images are sequentially formed on the label of the first page. FIG. 3a shows an image after passing the recording head 101 on the most upstream side in the transport direction, and FIG. FIG. 3c shows an image after passing through the recording head 103, and FIG. 3d shows a completed image after passing through the recording head 104 on the most downstream side in the transport direction.

  Only the print raster: 4n (n = 0, 1, 2,...) Is recorded by the recording head 101 on the most upstream side, and a masked image 301 is formed for each of the three rasters therebetween. For the sake of convenience, the width of one raster is drawn as if wide in the transport direction, but actually corresponds to one dot of the nozzle of the recording head. For example, if the recording head has a resolution of 600 [dpi], it is 42.3 [μm]. .

  When passing the next recording head 102, the print raster: 4n + 1 portion is complemented, and an image 302 is formed in which the two rasters between them are not recorded yet.

  Subsequently, when passing through the recording head 103, the print raster: 4n + 2 portion is complemented, and an image 303 is formed in which the remaining one raster is not recorded yet.

  After passing through the recording head 104 on the most downstream side in the transport direction, the print raster: 4n + 3 portion is complemented, and an image 304 corresponding to the recording data is completed.

FIG. 4 shows how images are sequentially formed on the label of the second page. In this page, the assigned raster for each print head is
Recording head 101: 4n + 1 (n = 0, 1, 2,...)
Recording head 102: 4n + 2
Recording head 103: 4n + 3
Recording head 104: 4n
And changed.

The image 401 after passing through the recording head 101, the image 402 after passing through the recording head 102 shown in FIG. 4a, the image 403 after passing through the recording head 103 shown in FIG. 4b, and the image 404 after passing through the recording head 104 shown in FIG. The image shown in FIG. 4d is completed after passing through the recording head 104 on the most downstream side in the transport direction.

FIG. 5 shows a state in which images are sequentially formed on the label of the third page. In this page, the assigned raster for each print head is
Recording head 101: 4n + 2 (n = 0, 1, 2,...)
Recording head 102: 4n + 3
Recording head 103: 4n
Recording head 104: 4n + 1
And further changed.

An image 501 after passing through the recording head 101, an image 502 after passing through the recording head 102 shown in FIG. 5a, an image 503 after passing through the recording head 103 shown in FIG. 5b, and an image 504 after passing through the recording head 104 shown in FIG. The completion of the image shown in FIG. 5d is still after passing through the recording head 104 on the most downstream side in the transport direction.

FIG. 6 shows how images are sequentially formed on the label of the fourth page. In this page, the assigned raster for each print head is
Recording head 101: 4n + 3 (n = 0, 1, 2,...)
Recording head 102: 4n
Recording head 103: 4n + 1
Recording head 104: 4n + 2
And further changed.

An image 601 after passing through the recording head 101, an image 602 after passing through the recording head 102 shown in FIG. 6a, an image 603 after passing through the recording head 103 shown in FIG. 6b, and an image 604 after passing through the recording head 104 shown in FIG. The completion of the image shown in FIG. 6d is still after the recording head 104 on the most downstream side in the transport direction has passed.

FIG. 7 shows how images are sequentially formed on the label of the fifth page. In this page, the assigned raster for each print head is
Recording head 101: 4n (n = 0, 1, 2,...)
Recording head 102: 4n + 1
Recording head 103: 4n + 2
Recording head 104: 4n + 3
And changed back to the same charge as the first page.

An image 701 after passing through the recording head 101, an image 702 after passing through the recording head 102 shown in FIG. 7a, an image 703 after passing through the recording head 103 shown in FIG. 7b, and an image 704 after passing through the recording head 104 shown in FIG. The completion of the image shown in FIG. 7d is still after the recording head 104 on the most downstream side in the transport direction has passed.

  As shown in FIGS. 3 to 7, the means for changing each print head assigned raster as shown in FIGS. 3 to 7 is synchronized based on the output of the rotary encoder 110 sent from the servo logic circuit 216 to the print head control circuit 208 in most cases. This can be realized by the signal and the hardware inside the print head control circuit 208. For example, in order to change the assigned raster for each page of the label, the label leading edge detection by the paper leading edge detection sensor 111 is reflected on the print head control circuit 208 There is also a method involving the processing of the CPU 202 in this part, and the processing flow will be described with reference to FIG.

  When the recording operation is started, the CPU 202 sets the first assigned raster of each recording head as follows (801).

Recording head 101: 4n (n = 0, 1, 2,...)
Recording head 102: 4n + 1
Recording head 103: 4n + 2
Recording head 104: 4n + 3
Thereafter, one page is recorded (802), and if the predetermined number is not completed (803-No), the assigned raster of each recording head is changed and set as follows (804).

Recording head 104: 4n (n = 0, 1, 2,...)
Recording head 101: 4n + 1
Recording head 102: 4n + 2
Recording head 103: 4n + 3
Then, the corresponding page is recorded (805), and if the predetermined number is not completed (806-No), the assigned raster of each recording head is changed and set as follows (807).

Recording head 103: 4n (n = 0, 1, 2,...)
Recording head 104: 4n + 1
Recording head 101: 4n + 2
Recording head 102: 4n + 3
Then, the corresponding page is recorded (808), and if the predetermined number is not completed (809-No), the assigned raster of each recording head is changed and set as follows (810).

Recording head 102: 4n (n = 0, 1, 2,...)
Recording head 103: 4n + 1
Recording head 104: 4n + 2
Recording head 101: 4n + 3
Then, the corresponding page is recorded (811), and if the predetermined number is not completed (812-No), the process returns to (801) and is set to the initial value again.

  When a predetermined number of recordings are completed (803-Yes, 806-Yes, 809-Yes, or 812-Yes), the process ends.

  As described above, by changing the assigned raster of the recording heads 101 to 104 for each predetermined division, the cumulative number of dots of ink ejected from each nozzle is further averaged, and the life of each recording head is As a result, it is improved.

  The recording apparatus of the present invention can be used for a high-speed and high-quality label printer and a large color printer.

It is a perspective view which shows the concept of the recording device recording part which implemented this invention. 1 is an electrical block diagram of a recording apparatus embodying the present invention. It is a figure which shows a mode that an image is sequentially formed in the label of the 1st page. It is a figure which shows a mode that an image is sequentially formed in the label of the 2nd page. It is a figure which shows a mode that an image is sequentially formed in the label of the 3rd page. It is a figure which shows a mode that an image is sequentially formed in the label of the 4th page. It is a figure which shows a mode that an image is formed sequentially in the label of the 5th page. It is an operation | movement flow of CPU which implemented this invention.

Explanation of symbols

101 Recording head (Bk1)
102 Recording head (Bk2)
103 Recording head (Bk3)
104 Recording head (Bk4)
105 Roll paper 106 Label 107 Recorded label 108 Conveyance motor 109 Feed roller 110 Rotary encoder 111 Tip detection sensor

200 host PC
201 Interface controller 202 CPU
203 ROM
208 Print Head Control Circuit 216 Servo Logic Circuit

Claims (2)

Medium conveying means for conveying a long recording medium in a predetermined conveying direction;
And four recording heads that eject ink of the same color,
The four recording heads are each responsible for recording on a raster in a direction intersecting the transport direction, thereby sharing four consecutive rasters to complete an image on a recording medium,
The recording data divided for each raster in the direction intersecting the transport direction is generated, and the divided recording data corresponding to the raster handled by each of the four recording heads is assigned to the corresponding four recording heads. Control means to transfer to,
Have
When the raster assigned to each of the four recording heads is changed for each page , the control unit changes the recording for each of the four recording heads according to a predetermined order. A recording apparatus. The medium transport means includes position detection means in the transport direction of the recording medium,
The recording apparatus according to claim 1, wherein a synchronization signal for starting recording of a raster image shared by the recording head is transmitted from the position detection unit.

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